Automatic alarm



spt. 6,1927. n V 1.641.218 J. W. JOHNSON AUTOMATIC ALARM Filed Auz. 13. 1925 i .Patented Sept. 6, 1927.

f UNITED .STATES Y i 1,641,278 l PATENT, OFFICE,

JOHN WILLIAM JOHNSON, OE AUOHLAND, NEW ZEALAND, AssIGNoE OE oNE-HALETO LUKE BERNARD.` DOUGHERTY, or HAMILTON, NEW'ZEALAND.

AUTOMATIC ALARM.

Application led August I3, 1925. Serial No.50,129.

This invention relates to ywarning devices and more particularly to that class of warning device which is adapted to beset in operation on any personinterfering withv or attempting to remove any article to which or on which such device is attached orv the article or articles to be protected are interfered with, moved, lifted or attempted to be carried away in any manner. y

According to the invention, the device when constructed Vasa separate unit, is contained in a casing for the like "having a hinged upper side or lid, adapted when the said device is set `ready for operation, tobe i position lby Vmeans of a` secured in its closed 26 suitable lock.

`The bottom of the casing is Vpositioned somev distance from the lower edges of the sides ot'- wthe same soA as to provide an enclosed space between the said bottom and 30 the article 'which it is desired toV protect and on which the device has lbeen placed or issupported.

A tubular member mounted inside the casing is. adapted to provide a` guide through which a rod is capable of a'certain amount of vertical `sliding movement, the lower end of the said rod passing `through the bottom of the casing and projecting, a short distance into the space between the 40 said bottom and the article on which the latter is resting. v

A loose ball or the likeis positionedbetween the lower end of the vertical rod and ythe article to be protected, said ball supporting or retaining the rod lat or near the uppermost limit of its sliding movement in the tubular guide.

The upper end of the vertical sliding rod is biiurcated and is adaptedto support a balance arm, one end of which isweighted to render it heavier than the other' end` The lighter end of the balance arm is provided `with a fseating on which a ball is adapted `to be supported,pthe .weight of said ball being such that the Weights of the two ends of the said balance arm are equalized and the latter is supported horizontally across the upper end of the vertical rod.

. Electric contacts on either end of' thebal ancearm are held out of contact with ad-` justable contacts inside .the casing so long as the said'balance arm is retained in its horizontal position and so long as the vertical sliding rod remains at the uppermost limit of its sliding movement.

i On the device being moved, tilted or lifted in any manner, either the ball will be dislodged from its seating. on the lighter end of the balance arm,- whereupon `the heavier end oi the latter willy fall to close the electric contacts vand complete an electric circuit, or the ball will be moved lfrom underneath the lower endfof the verticalV rod, and the latter will drop in its tubular guide causing the balance arm as it also dropsto close the electric circuit and set in operation an alarm sounding meanswhich will continue to operate until such time as the electric circuit is disconnected.

The invention will be more particularly described with the aid of the accompanying drawing, wherein i f f n Figure 1 is a sectional perspective view of the device constructed as a separate unit, showing the vsame Vset ready for operation.

Figure 2 is a sectional elevation of the device as shown in Figure l, but showing the same s et in operation owing to thedevice having been'slid orlifted off of the article Vto be protected,'and

Figure 3 is a similarA view to. Figure 2 showing the, alarm set in operation by the ball being dislodged from the lighter end of the balance arm.

A strong casing l is provided with a removablelid 2 adapted to be secured in its closed position vby means of a convenient lock 2a. The bottom 3 of the Vcasing v1 is positioned some distance above the lower edges of the sides of the same so as to provide a space 4 between the said bot-tom 3 and the article, surface or the like on which lthe device is supported or stands.

A ball 5 located in the space 4 is adapted to support the lower end of a vertical rod 6 which projects through the lbottom 3 and is slidable vertically in a tubular guide member 7 The effect of placing the ball 5 under the'lower end of the rod 6 is to retain the latter at or near its uppermost limit of sliding vn'iovement through, the guide 7, as shown in Figures 1 and 3 of the accompanying drawing.

The upper end of the rod G is bifurcated and hasmounted therein, by'means of a suitable knife edge fulcruni pin S, a balance arm 9 one end of which is weighted as at 10 in order to render it heavier than the other end of the said balance arm.

The lighter end of the balance arm 9 is provided with a seating 11 adapted to support a ball 12 the weight of which is just sutlicient to counteract the effect of the Weightedv portion 1.0 of the other end of the balance arm and so balance or restore the latter to equilibrium.

The balls` 5 and 12 having` been placed in position as herein described, the device is in the position shown in Figure 1 of the accompanying drawing.

The ends of the balance arm 9 are provided with electric contacts 13 and 15, and electric contacts 14 and 16 in the electric circuit of a suitable battery 15 and bell or other alarm soundng means 20, are mounted adjustably on vertical supports or lguides 17 within the casing 1.

Should the device be lifted off, or slid along the surface of the article to be pro-- tected and on which latter the device is supported or stands, the ball 5 is either rolled out from under the rod 6, or else the latter drops in its guide 7 as the box isv lifted off the article or surface on which the ball rests.

The effect of this is to cause the ball 12 to be dislodged from its seating 11 by the disturbance of the equilibrium of the balance arm 9 as it falls with the rod 6, and the contacts 13 and 1a, 15 and 16 are thereby closed to cause electric current to pass through the balance, arm 9, rod G, and tubular guide member 7, from which latter -it is led through a wire or wires to the bell 20 or other Warning means located in 4the casing 1.

In the case of the device being lifted ofi" of or slid from on top of the article to be protected. as herein before described, it is not essential for the ball 12 to be dislodged from its seating 11 before the warning bell 2O will operater` as the falling of the balance arm 9, even though the latter retains its equilibrium, is suflicient to bring the contacts 13 and 15 into touch with the contacts 14 and 16.

Where the article to` be protected by the device is in itself of a portable nature, it might be possible to carry away both the article and thevdevice supported on the latter without operating the alarm, were the displacement of the ball 5 alone to be relied on to cause the .closing of the electric contacts.

In such a case, however, the ball `12 being only retained on its seatingl 11 by means of a slight depression in the centre of the latter, is easily dislodged and will only remain in position so long as the casing 1 and balance arm 9 remain absolutely steady.

Should it be attempted to remove the dc- Vice without moving it from the top of Jihe article to be protected, the slightest movement will cause the ball 12 to fall from .its seating, whereupon the weighted end of the balance arm 9 will fall and the contact 15 thereon comev into touch with the contact 16 in the electric circuit of the bell 20 to operate the latter.

The alarm 20 can only be put out of operation by unlocking the lid 2 of the casing 1 with the proper key and then ,disconnecting the electric circuit of the bell 2O vor the like.

The contact 15 on the heavier end of the balance arm 9 is preferably of hollow rectangular or ring shape, the contact 16 on the upright 17 being in the form of a pin which normally projects inside the said hollow rectangle or ring but does not touch the latter` thereby providing that should. the device be turned on its side or upside down in an atempt to stop the alarm once the latter has commenced ringing, no matter in what direction the balance arm 9 lies, the said contacts will still be enabled lto touch one another and the alarm to continue ringing.

The vertical sliding movement of the rod is preferably limited by` means of a. slot 18 in the side of the tubular guide member 7 and a pin 19 projecting from the side of the rod 6 andentered in the said slot 18. This slot and pin prevent rotation of the balance arm 9 and rod 6 out of their normal positions, and consequently ensures that the conta-cts on the said balance arm will at all times be directly over the contacts on the nprights 17.

Having now described my said invention, I declare that what I claim and desire to obtain by Letters Patent of the United States of America, is

1. A theft-foil circuit closer including a sliding support, a balance arm fulcrumed on said support and forming one pole of the circuit closer, means constituting the otherpole, in operative proximity to said balance arm., and a free ball normally positioned beneath said sliding support for holding said arm out of Contact with said other pole.

2. A theft-foil circuit closer including' a sliding support, a balance arm fulcrumed on said support, means constituting afixed pole of the circuit closer, a conductive loop carried by said balance arm freely surrounding said fixed pole and itself constitilting the other pole, and aI free ball normally positional beneath. said sliding support for holding said balance arm at such lll) elevation as to maintain said poles out of `slidingsupport, a balance arm fulcrumed 'on said Support forming one pole of the circuit closer, means constituting the other pole in operative proximity to veaidbalance arm and balls on one of Which said support freely rests, the other being balanced on said arm, and each being operable to close Said circuit, the one by body translatory movement of said balance arm due to Sliding movement of said support and the other by pivotal movement of the arm about its 4. A theft-foil circuit closer including a sliding` support, a balance arm fulcrumed 0n said support and forming one pole of the circuit closer; means constituting the other pole, inoperative proximity to said balance arm, and a free ball normallyvpositioned on said balance arm for maintaining the equilibrium thereof said ball being rdisplaced by tilting of said circuit closer.

Signed at Auckland, in the Provincial District oit" Auckland, in the Dominion of New Zealand, this 18th day of July, A. D. 1925;

JOHN WiLLIAM JOHNSON; 

